CODEWITHSUNDEEP
libgdxfragment-shaderscene2d
gogonapel
gogonapel

Reputation: 788

Scene2D fadeIn fadeOut breaks when using shaders

I'm using a simple shader to do a vignette transition effect in my game on each screen load (picked up from this book). I use this transition effect in my menu screens. All is well with the exception that my fadeIn , fadeOut animations that I apply to the buttons of the menu don't have any effect with this added shader; in fact no alpha value has any effect on any actor on the screen when I use this shader.

Here's the vertex shader:

...
gl_Position = u_projTrans * a_position;
v_texCoord = a_texCoord0;
v_color = a_color;

And the fragment shader:

...
vec4 texColor = texture2D(u_texture, v_texCoord);
...
gl_FragColor = vec4(texColor.r, texColor.g, texColor.b, texColor.a);

How can I fix the alpha issue so actors render the alpha properly with the shader ?

Maybe the fragment blow will work? But how do I set the alpha for every actor of the screen?

uniform float ALPHA;
...
gl_FragColor = vec4(texColor.r, texColor.g, texColor.b, texColor.a * ALPHA);

Upvotes: 0

Views: 149

Answers (1)

Tenfour04
Tenfour04

Reputation: 93601

Fade animations utilize the alpha of the vertex color. This is passed into SpriteBatch which passes it to the vertex shader as a_color. Your vertex shader already passes the color to the fragment shader as v_color, so in your fragment shader, you need to multiply the final alpha by this fade value:

Fragment shader:

varying LOWP vec4 v_color;
//...
gl_FragColor = vec4(texColor.r, texColor.g, texColor.b, texColor.a * v_color.a);

Upvotes: 1

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